3 transistor AM radio 700 KHz - 1.6 MHz

The radio works on 12 Volt. A simple radio usable for local radio stations on AM between 700 KHz and 1.6 MHz. You need an external antenna from approx 10 meter outside or an indoor antenna from approx. 4 meter. Connect an indoor antenna directly to the base from the first transistor ( max. 2 meter long) or use a coupling capacitor between 100 P and 500 P (2 - 4 meter long). Experiment a little bit with the antenna capacitor. With a 10 meter long wire antenne outside you can receive radio stations from approx. 600 km or more far away. I received radio China, a radio station from the US and radio stations from eastern europe. The second transistor has two functions: tuning + oscillator. In the oscillator mode the oscillator is modulated by the antenna signal. This gives a better selectivity and better receiving results. You can find more sophisticated + easy to make radio schematics (superheterodyne) in my books (author Ko Tilman), "Retro Radio" (Dutch text), published by Elektor International Media in the Netherlands, and "2-10 MHz Shortwave receiver and 1 transistor VFO's (published by Lulu on the Lulu website). Corrections to the video: BF 547 b = BC 547 b, "condensator" (Dutch) = "capacitor".

Category:

Science & Technology

Tags:

• AM
• radio
• 700
• KHz
• 1.6
• MHz
• local
• stations
• heterodyne
• receiver
• tuning
• HAM
• amplitude
• modulated
• amateur

[AndyDaviesByTheSea]

Hi there, it looks like you’re having a lot of fun with your radios. Seeing the double layer of ‘bread board ‘gives a different meaning to the term, ‘Multi layer’ boards, hi hi. Well done, nice demo.

Kind Regards ... Andy

[radiofun232]

Thanks Andy, never thought about it as a multilayer breadboard, but it makes sense. Indeed it is fun to make these circuits and I am always thinking about new figurations.

[cogito451]

Hello, Mr. Tilman. I was wondering: Is the output of this circuit strong enough to drive a speaker or headset on its own, or does the signal require further amplification?

[radiofun232]

It needs further amplification by means of a 1 Watt audio amplifier. In the video I used a 1 Watt audio amplifier and a real loudspeaker box to give the sound a certain quality.

[cogito451]

Thanks.